1. Field Of The Invention
The invention generally relates to a method of preparing a high density particulate slurry capable of being pumped into a subterranean formation. The high density particulate slurry can be utilized to perform gravel packs or effect consolidation of unconsolidated formations and is particularly useful in setting well casing in deviated wellbores.
2. Description Of The Prior Art
Increased emphasis is being placed on proper initial completion of a well as the value of nonrenewable natural resources increases and the costs associated with production escalate. While such emphasis is especially felt in the area of hydrocarbon production, production of other valuable fluids such as groundwater also emphasizes the need for efficient production techniques.
The general sequence of cased hole and open hole completions is set forth in Fitzpatrick, U.S. Pat. No. 4,917,188, the entire disclosure of which is incorporated herein. The general sequence of performing a cased hole completion includes drilling the hole, setting and cementing casing, perforating the casing, cleaning the perforations, performing sand control steps and stimulating the formation to facilitate production. The general sequence of performing an open hole completion includes drilling the hole to the bottom of the deepest target formation, setting and cementing casing to the target formation, drilling a hole through the target formation, reaming the hole to remove damage from drilling operations and stimulating the exposed largest formation. If sand control is required a gravel slurry is introduced into the wellbore and placed between a slotted liner or screen and the exposed face of the target formation.
A variety of techniques have been developed in the art to address sand control problems. One such method involves the process of injecting chemicals into the formation to effect grain-to-grain cementation. Techniques for accomplishing this successfully are perhaps some of the most sophisticated undertaken in completion work. In closely related methods, sand or other particulate are chemically treated, such as by coating with an epoxy or plastic resin, and then injected into the wellbore through a slotted liner or screen in the production zone to effect consolidation. Such a resinous particulate slurry is described, for example, in Copeland, et al U.S. Pat. No. 4,074,760 or in Murphey, et al U.S. Pat. No. 4,829,100, the entire disclosure of which is incorporated herein by reference.
While conventional gravel packing techniques are highly successful when employed in vertical wellbores, various problems arise when highly deviated or horizontal wellbores are sought to be treated.
Contemporary completion techniques incorporating provisions for sand control describe the introduction of the resin particulate slurry into the wellbore in such a fashion as to cause laminar flow of the slurry in the annulus between the wellbore and the production casing. This results in undesired settling or "voiding" in deviated wellbores which reduces production efficiency of the gravel pack. The laminar flow also allows time for the formation to dehydrate the resin slurry causing premature and often unsatisfactory setup of the consolidation adjacent the production casing.